By Nancy McVicar
Men diagnosed with prostate cancer have almost a dozen different choices of treatment, says Dr. Srinath Sundararaman, director of radiation oncology at Memorial Cancer Institute in Pembroke Pines, from removal of the gland surgically to a variety of less invasive procedures. One of the newer options and least invasive involves a technique called CyberKnife robotic radiosurgery which requires no anesthesia or cutting.
“Men have chosen external beam radiation because it’s not invasive, and it has become very good, very precise over the last decade,” he says. But this approach, called IMRT, usually requires the patient to go for treatment five days a week for up to eight weeks.
CyberKnife can achieve similar results with a fraction of the time commitment: five days of 70 to 90 minutes duration each day, Sundararaman says.
CyberKnife uses a combination of image-guided cameras, robotic technology and computers to concentrate radiation on the diseased gland while limiting exposure to healthy tissue.
During the treatment, the CyberKnife is able to track any movement of the prostate gland caused by air passing through the rectum or the bladder filling so the radiation is confined to the target area and spares healthy tissue around it.
“Gold markers are placed into the prostate as surrogates and they exactly tell us where the prostate is, and if it moves, the machine moves with it,” Sundararaman says. “The machine looks every three seconds, and if the gland has moved, it makes the adjustment.”
The best candidate for the procedure is someone considered a low-risk patient based on his PSA (a blood test that measures prostate-specific antigen) and Gleason scores, markers of the aggressiveness of the disease, stage, and other prognostic factors.
“In prostate cancer, we’re talking less about stage and more about risk based on what the pathologist tells us about how angry the cells are. So a person considered low risk is an ideal candidate,” he says.
Because the technique is relatively new, several thousand cases compared with tens of thousands of cases treated with older technologies, doctors who use CyberKnife include their cases in a national registry.
In Florida, the Medicare intermediary does not reimburse for CyberKnife treatment for prostate cancer, Sundararaman says, even though Medicare does cover it in other states, including California and New York. As a result, some men on Medicare opt for the eight-week external beam radiation treatment instead because it is covered.
One goal of the registry, Sundararaman says, is to show how effective the treatment is compared with other treatments.
After the treatment, patients are monitored at intervals by testing their PSA levels to make sure there is no recurrence.
“We want eight to 10 years of data eventually,” he says, and about seven years worth has been collected. “And we’ve seen the PSA control is excellent.”
“The side effects profile is extremely low,” he says. “Patients may experience some frequency of urine, at first, rarely burning, but that should subside within a month at most. This treatment is not going to hurt the quality of life. The quality of orgasm is not changed as a result of this.”